"Quick - name the most important personal computer of the late 1970s and early 1980s. Those of you who mentioned the legendary Apple II - that's fine. I respect your decision. Forced to think objectively in 2012, I may even agree. But if you just named Radio Shack's TRS-80, you made me smile. Your choice is entirely defensible. And back in the TRS-80's heyday, I not only would have agreed with it but would have vehemently opposed any other candidate."

The TRASH-80... you either swore by it, or swore at it. This was the first computer I wrote programs for. It was nothing special. I preferred the Atari 8-bit computer, which is what I ended up buying when I finally got the money to buy my own computer.

The best part of the TRASH-80? The CPU - the Z80 was a joy to program... perhaps the best of the 8-bit CPUs. However, the 6502 was clearly king of the day, being in nearly every 8-bit computer of any worth.

I learned to program in Z80 assembly in 2000 for a job. Kind of late in the game. Sometimes I wish I could go back at 8 with my current knowledge and apply that now useless Z80 skills to blow everyone's minds. (and invest my lunch money in Apple stocks).

You CAN blow people's minds with your new RAD skillz! Folks looking to do some Z80 programming often do their own programs for the old Sega Master System, or the MSX computer. You can find flash carts for the SMS to even run your game on the real machine.

the Z80 was a joy to program... perhaps the best of the 8-bit CPUs. However, the 6502 was clearly king of the day, being in nearly every 8-bit computer of any worth.

Hm, the families of MSX, Amstrad/Schneider, and Spectrum (plus numerous clones) had some worth, I think. And what about many ~business CP/M machines?
In the 6502 camp (sorting http://en.wikipedia.org/wiki/List_of_home_computers by CPU type) worthy are the families of Apple II, Commodore, Atari, and Acorn.
So perhaps fairly comparable proportions, especially considering that only the Apple II was extensively cloned in the latter group - but in the former you have Spectrum clones and numerous MSX & CP/M manufacturers.

And I can see some very clear geographical delineation, Z80 more used in home computers (the 8-bit micros we most remember) from outside North America, more popular outside of it (and some mostly Western European, culturally at least, countries) - perhaps that contributes to your perception?